Advances in microprocessor and telecommunication technology have led to wide spread deployment and adoption of mobile devices, such as wireless mobile phones and PDA. For wireless mobile phones, in addition to wireless telephony, the late models are often equipped with advanced capabilities, such as calendar, address book, games, access to the World Wide Web (WWW), emails, instant messaging, and so forth. Similarly, for PDA, in addition to calendar and address book functions, the late models are often equipped with advanced capabilities, such as wireless telephony, word processing, spreadsheets, and so forth. In other words, for advanced models, there are increasing cross over or convergent of the functionalities.
However, because of the compactness of the mobile device, typically only limited number of control keys are available to operate these advanced functionalities. For example, in the case of wireless mobile phones, typically only a 12-key keypad plus a handful of control buttons are available, and in the case of PDA, only a handful of control buttons are available. As a result, usability and in turn the user experience of these advanced functions are poor, which in turn leads to the reduced acceptance of the advanced functions, removal of economic incentives for further development and introduction of the advanced functions.
Some prior art mobile devices support the provision of addition control keys, such as an alphabet-keys, through the attachment of a peripheral device, such as a keyboard, to an I/O port of the mobile device. However, as described earlier, because of the inherit compactness of mobile devices, only limited number of I/O ports, typically one, is available for attachment of external peripherals.
Thus, a need exists to provide more expansion I/O ports to allow more external peripherals to be attached to a mobile device.